<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
        <script src="../js/jquery-3.4.1.min.js"></script>
        <style>
            div{
                width:100px;
                height: 100px;
                background:yellow;
            }
        </style>
        <script>
            $(function(){
                $("input:first").click(function () {
                    $("div").css("display","none");
                });
                $("input:last").click(function () {
                    $("div").css("display","block");
                });
            });
        </script>
    </head>
    <body>

        <input type="button" value="隐藏第一个div">
        <input type="button" value="显示第一个div">
        <div>div1</div>

    </body>
</html>